1. Field of the Invention
The present invention relates to case frame manufacturing. More particularly, to a method for manufacturing hairlines within a case frame to create elegant designs therein.
2. Description of the Related Art
To improve the appeal of products to users, more esthetic designs are being applied to the products case frame. The case frames, which define an outer surface of the product or apparatus, are being designed with more elegant and appealing to the user by performing a surface processing. Examples of the surface processing include a hairline processing. Generally, a hairline processing represents the drawing of one or more thin lines on a metal plate, such as aluminum and stainless steel. The hairline processing prevents glaring caused by the high shine and glossy surface of the metal, hides or reduces the noticeability of scratches or damages in the surface, and makes a metal product more appealing and elegant. As high-priced digital home appliances become more popular and in their demand increases, it becomes important that such products include visual characteristics that represent sophistication and elegance design. Thus, surface processing techniques and equipment for performing hairline processing are constantly being improved upon to realize increased esthetic demands.
FIG. 1 is a cross-sectional view of a series of processes schematically illustrating a conventional method for hairline processing.
Referring to FIG. 1, which are represented as (Process A)-(Process C), a metal plate 100 of a predetermined shape is prepared through well-known blanking and punching processes (process A). The metal plate 100 has a surface 101 on which the hairline surface process is to be performed and which is to be exposed to the outside. Defects in, or foreign material(s) on, the surface 101 may be removed using a buffing machine with a sand paper facing. After that, the surface 101 is processed to become hairlines 102 using a predetermined tool (process B). The tool used for the hairline processing may be a brush, a sand paper, a luffa, etc. During the hairline processing, the tool may cut the surface 101 to form regular and/or irregular hairlines. For example, in a cross-section corresponding to line S-S illustrated in the plate 100, a depth cut by the tool is irregular. In addition, the cut depth may be regular or irregular also in, in a direction normal to the cross-section (i.e., a lengthwise direction of the plate). After that, the hairlines 102 are coated with a predetermined paint material 110. Preferably, the paint material 110 is coated to a predetermined thickness on the hairlines 102 to form a coated surface 111 that can effectively express irregularities of the hairlines 102 (process C).
The hairline processing method, shown by processes A to C, is generally applied to only a metal whose surface hardness is relatively low (for example, aluminum, magnesium, etc.). In the case where the metal case frame is used for an electronic apparatus, a current may leak to the case frame. Furthermore, the conventional method for processing hairlines forms hairlines in the metal plate 100 through a post process of the processes B and C (FIGS. 1B, 1C). Therefore, since the conventional method for processing hairlines highly depends on the post process, the processing yield fall, which results in increased costs.
FIG. 2 illustrates a case where a defect occurs when the conventional method for processing hairlines described in FIG. 1 is applied to a metal or non-metal plate.
Referring to FIG. 2, the conventional method for processing hairlines described in FIG. 1 may process hairlines as illustrated in the process C of FIG. 1. However, as illustrated in FIG. 2, hairlines 102 formed in advance may not be coated with a predetermined paint material 120 of predetermined thickness in all areas. Thus, the coated surface 121, having unequal depths in some areas, may not properly express the hairlines 102.
In addition, the conventional method for processing hairlines illustrated in FIG. 1 may be similarly applied to a non-metal plate. For example, a surface of a non-metal plate forms a surface in which hairlines have been formed using corrosion, electroforming, a laser, etc. instead of means such as a brush, a sand paper, etc. as described with the regard to the process illustrated in FIG. 1. After that, the surface in which the hairlines are formed is coated with a predetermined paint material. FIG. 2 may, thus, also illustrate hairlines formed using corrosion, electroforming, a laser, etc. that are buried within the predetermined paint material, and are not properly expressed. That is, fine irregularities of the hairlines vanish due to the uneven thickness of paint material in some areas. Therefore, patterns a little thicker than fine patterns need to be formed in a non-metal material using a processing such as corrosion, electroforming, a laser, etc. Therefore, it is difficult to properly express fine hairlines using the method for processing the non-metal plate using means such as corrosion, electroforming, a laser, etc., and consequently, texture of a real metal surface cannot be expressed.